<!--
Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<!--
/**
 * @group Polymer Core Elements
 *
 * The `core-iconset-svg` element allows users to define their own icon sets
 * that contain svg icons. The svg icon elements should be children of the
 * `core-iconset-svg` element. Multiple icons should be given distinct id's.
 *
 * Using svg elements to create icons has a few advantages over traditional
 * bitmap graphics like jpg or png. Icons that use svg are vector based so they
 * are resolution independent and should look good on any device. They are
 * stylable via css. Icons can be themed, colorized, and even animated.
 *
 * Example:
 *
 *     <core-iconset-svg id="my-svg-icons" iconSize="24">
 *       <svg>
 *         <defs>
 *           <g id="shape">
 *             <rect x="50" y="50" width="50" height="50" />
 *             <circle cx="50" cy="50" r="50" />
 *           </g>
 *         </defs>
 *       </svg>
 *     </core-iconset-svg>
 *
 * This will automatically register the icon set "my-svg-icons" to the iconset
 * database.  To use these icons from within another element, make a
 * `core-iconset` element and call the `byId` method
 * to retrieve a given iconset. To apply a particular icon inside an
 * element use the `applyIcon` method. For example:
 *
 *     iconset.applyIcon(iconNode, 'car');
 *
 * @element core-iconset-svg
 * @extends core-meta
 * @homepage github.io
 */
-->

<link rel="import" href="../core-iconset/core-iconset.html">

<polymer-element name="core-iconset-svg" extends="core-meta" attributes="iconSize">

  <script>

    Polymer('core-iconset-svg', {


      /**
       * The size of an individual icon. Note that icons must be square.
       *
       * @attribute iconSize
       * @type number
       * @default 24
       */
      iconSize: 24,
      type: 'iconset',

      created: function() {
        this._icons = {};
      },

      ready: function() {
        this.super();
        this.updateIcons();
      },

      iconById: function(id) {
        return this._icons[id] || (this._icons[id] = this.querySelector('#' + id));
      },

      cloneIcon: function(id) {
        var icon = this.iconById(id);
        if (icon) {
          var content = icon.cloneNode(true);
          content.removeAttribute('id');
          var svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
          svg.setAttribute('viewBox', '0 0 ' + this.iconSize + ' ' +
              this.iconSize);
          // NOTE(dfreedm): work around https://crbug.com/370136
          svg.style.pointerEvents = 'none';
          svg.appendChild(content);
          return svg;
        }
      },

      get iconNames() {
        if (!this._iconNames) {
          this._iconNames = this.findIconNames();
        }
        return this._iconNames;
      },

      findIconNames: function() {
        var icons = this.querySelectorAll('[id]').array();
        if (icons.length) {
          return icons.map(function(n){ return n.id });
        }
      },

      /**
       * Applies an icon to the given element. The svg icon is added to the
       * element's shadowRoot if one exists or directly to itself.
       *
       * @method applyIcon
       * @param {Element} element The element to which the icon is
       * applied.
       * @param {String|Number} icon The name the icon to apply.
       * @return {Element} The icon element
       */
      applyIcon: function(element, icon) {
        var root = element;
        // remove old
        var old = root.querySelector('svg');
        if (old) {
          old.remove();
        }
        // install new
        var svg = this.cloneIcon(icon);
        if (!svg) {
          return;
        }
        svg.setAttribute('height', '100%');
        svg.setAttribute('width', '100%');
        svg.setAttribute('preserveAspectRatio', 'xMidYMid meet');
        svg.style.display = 'block';
        root.insertBefore(svg, root.firstElementChild);
        return svg;
      },
      
      /**
       * Tell users of the iconset, that the set has loaded.
       * This finds all elements matching the selector argument and calls 
       * the method argument on them.
       * @method updateIcons
       * @param selector {string} css selector to identify iconset users, 
       * defaults to '[icon]'
       * @param method {string} method to call on found elements, 
       * defaults to 'updateIcon'
       */
      updateIcons: function(selector, method) {
        selector = selector || '[icon]';
        method = method || 'updateIcon';
        var deep = window.ShadowDOMPolyfill ? '' : 'html /deep/ ';
        var i$ = document.querySelectorAll(deep + selector);
        for (var i=0, e; e=i$[i]; i++) {
          if (e[method]) {
            e[method].call(e);
          }
        }
      }
      

    });

  </script>

</polymer-element>
